Important: References and Useful IntFiction Threads, below, have the answers to a huge number of things that may be baffling you that you couldn’t find in the docs. Exploring their links is rewarding.
Inform 7 10.1 (current release)
I7 10.1.2 and IDEs for Mac, Windows, and Linux. The v10 release notes detail changes and bugfixes.
- Docs for Inform 7 10.1 and IDE (integrated development environment)
- 10.1 compiler and tools docs/literate source
- 10.1 bug tracker
- Inform Evolution: proposals for future development
- v10 discussion thread
- WI 27.14: Longer extracts of I6 code details on what I6 is permitted in inclusions
- Linux IDE installation notes
10.1 renders some specifics on this page out of date
9.3/6M62 (previous, released 2015-12-24)
- I7 9.3/6M62 language and IDE docs, included in its IDE
- Writing with Inform read-through with commentary (invaluable)
Tutorials
Excellent: start here.
- Allison Parrish’s Inform 7 Concepts and Strategies (6M62)
- Carolyn VanEseltine’s Welcome to Adventure: A Quick-Start Guide to Inform (6L38)
- Drew Cook’s Inform Basics
Installation
@Juhana’s Borogove lets you edit and run I7 (v10, 6M62, or 6G60) online: experiment without installing anything. Borogove snippets allows sharing code examples.
Official packages mentioned below available at I7 Downloads.
MacOS
Use the package on the I7 site; don’t use the App store’s. There are known issues with slowness on machines with TouchBars and the cursor disappearing in Dark Mode. An unofficial MacOS IDE release addresses these. Testing examples in Extension Projects doesn’t work.
Windows
Use the package on the I7 site (said to work with any version of Windows from XP SP 3 on). Or there’s a current beta release of a new Windows version that allows compiling for 6L02 and 6L38 as well as 6M62. It’s 64-bit-only, and has been tested only on Windows 10, but may work with older versions. Be warned that there have been multiple reports of security/antivirus programs causing problems with it: Avast, AVG, Windows Defender.
Linux
The 6M62 IDE package have uses GTK2; for a long time, GTK3 has been the norm, making the IDE hard to build on a modern Linux.Unofficial rpm/deb IDE packages
The official download page also offers a CLI-only version for Linux, which comes with “the cheesy Perl interface”. Or consult How to use ni, inform6, and cBlorb by CLI for info on using those commands directly. Some projects to help are Vimform7, the Inform 7 extension for VS code, Spaceformacs, and inf7.
Versions of ni prior to 6M62 are incompatible with Linux kernels >= 4.11 (from 2017). To build for 6L38 or older an old Linux in a VM or Windows Inform in WINE are the options (or for 6G60 use playfic.com online).
The official packages include components that have more recent versions. Some updates:
- Inform 6 6.41; Inform 6 6.41 for Windows (zip archive)
- Glulx Entry Points and Glulx Text Effects by Emily Short
- the Quixe, Parchment, and Vorple templates
Versions
Most things written about 6L02 or 6L38 remain relevant for 6M62. 6L02 had many backwards-incompatible changes: code written for 6G60 or earlier is unlikely to compile in 6L02 or later. This post usually notes the version as of which something was current. The Change Log has exhaustive details:
- The Change Log (comprehensive)
- Change Logs per release
- Change log in Mantis (the former bug tracker)
Manuals/Books
The Inform 7 Handbook by Jim Aikin (6L38); the I7 Handbook in PDF/ODT; an at-cost print-on-demand Inform 7 Handbook is available; I7 Handbook for 10.1 draft.
Ron Newcomb’s Inform 7 Programmer’s Manual (6G60). Overall written for an audience of experienced programmers, but with sections that will be useful to any I7 author: some are linked in References below. (Its previous edition was “Inform 7 for Programmers”.)
@aaronius’ book, Creating Interactive Fiction with Inform 7. It was for 6E72; Creating Interactive Fiction with I7’s errata provide updates for 6G60. Creating Interactive Fiction’s publisher lists the physical book as available to order and B&N sells an epub of Creating Interactive Fiction for the Nook. (There was never a legitimate PDF version for sale; if you see such, it’s… not legitimate.)
Jason Boyd’s Inform 7 Introductory Guide (6M62)
References
- Oliver Reiser’s I7 cheatsheet (6G60)
- @emshort’s rules flowchart (PDF) (5U92) illustrating the turn sequence
- Otis the Dog’s Standard Rules Actions reference (6M62)
- The Looking action and the activities and rules involved
- Which action rulebook to use: Is there a special syntax for dropping something in a conditional? - #12 by Dizzydonut, Rule is compiling but is ignored (Solved) - #4 by HanonO, What Rulebook? - #11 by Juhana, The perils of INSTEAD, Message for failed actions - #4 by Zed, Verb confusion- trying to feed my animals - #10 by Draconis
- Scope and visibility; Scope and visibility II
- Spatial and other relations between objects; Spatial relations addendum
- Action / Grammar Token reference, Action Patterns
- Definite/indefinite articles & improper/proper, singular/plural names in thing creation
- Times, Turns, and Tenses details on counting occurrences of actions, and using past tense in conditionals; Chronological records; chronological record maintenance details, Reporting and changing state - #11 by otistdog
- Nathanael’s Cookbook includes a useful reference to I7 line break behavior.
Compilation produces a Project Index viewable in the IDE lots of details about I7, including things not in the docs: it’s the closest thing to a reference manual. Its Phrasebook Index section (Phrases, Lexicon, Relations, Verbs) is good to check (along with the docs’ General Index) when you half-remember something you’ve heard of and need to find the right term to look up.
The actual syntax the I7 compiler uses to parse I7 code is in Languages/English/Syntax.preform in your installation’s Internal directory. The Backus-Naur Form syntax provided isn’t accurate. See the Syntax.preform documentation PDF (6L02). Syntax.preform also lets you see what irregular verbs and plurals Inform 7 handles and how.
Extensions
Counterfeit Monkey’s Extensions: beyond the many unique extensions, many other extensions included here are modified from their original versions.
Separate from the Authoring > Inform 7 category here, there is a Technical Development > Inform Extensions category chiefly discussing issues with existing published extensions
Glulx/Glk extensions ecosystem
Extension Writing Guides:
Standard Rules
I7 includes the Standard Rules with every game. They’re well-commented and the authority on the I7 World Model and I7’s defaults (they used to be labeled Appendix A of the documentation). They can be browsed in the IDE. (See “Contents” within any compiled game.)
Note the warning in Writing in Inform 27.14: things in the SR that look modifiable may not really be; they could be interdependent with something hard-coded in the compiler. And beware that all of the past three versions’ Standard Rules (6L02, 6L38, 6M62) are marked Version 3/120430, but each is different. (Likewise, 6E59 through 6G60’s Standard Rules are all marked Version 2/090402 but each is different.)
Games/examples with available Source Code
- Alex Proudfoot’s ports of The I7 Standard Examples, including @emshort’s Bronze (6M62)
- Hadean Lands (6G60),Andrew Plotkin’s other games (various)
- @Draconis’ Scroll Thief, Scroll Thief Bitbucket repo (6G60), Enigma of the Old Manor House (6M62)
- Chin Kee Yong’s The Weight of a Soul (6M62)
- Victor Gijsbers’ Kerkerkruip (6M62)
- @Juhana’s Sparkle (6L02)
- Jack Welch’s re: Dragon, a Vorple I7 game with a non-standard interface (6M62)
- Crowther and Woods’ Adventure (6M62)
- Ryan Veeder Expo for Good IF Event 1: Beautiful Source Code (6M62)
- Andrew Schultz’ games
- Aaron Reed’s Blue Lacuna
- Brian Rushton’s Grooverland
- IFDB search for I7 games with source code from 2016 on (6L38 and 6M62)
- Many Inform games’ source code on the IF archive. Not labeled with versions – some are old; some are recent.
- Cragne Manor by divers hands (6M62)
- @emshort’s Counterfeit Monkey (6M62) Especially worth examining if you’re writing a large game or concerned with performance: it’s one of the larger I7 games and has been extensively optimized. Older Counterfeit Monkey source prior to optimization and reorganization.
Inform 6
I7 compiles to Inform 6 before that gets compiled to Glulx or z-code. The Inform 6 Standard Library isn’t involved; I7 uses the I6 Template Layer that every Inform installation has under Internal/I6T. These used to be labeled Appendix B of the documentation: their comments often document things that aren’t documented elsewhere.
There are places where the best or only way to do something is by interacting directly with the I6 layer (many extensions do so) and other places where I7 behaviors can be better understood by understanding how they’re an artifact of I6 representations or where reading your project’s auto.inf, the I6 code that I7 generated, is useful to investigate problems.
- Designer’s Manual (DM4) / Reference Addendum
- I6 Technical Manual
- Translation of I6 Entry Points into I7 (4X60)
- Much more at The List of Inform 6 Documentation
Useful IntFiction threads/posts
- The first thing you need to understand about Inform is
- Most common 'mistakes' and 'crutches' for those starting out with inform 7?
- The hidden secrets of Inform 7
- Command-line Inform 7: how to use ni, inform6, and cBlorb by CLI for 9.3/6M62 (includes details on a project’s files and directory structure)
- Performance Best Practices (there are a couple of expensive things to avoid, but there’s no substitute for profiling to see where your game is spending its time)
- Good coding style in Inform 7
- QA: Checklist for authors of IF and Inform 7 IF in particular • One tester's game polish tips for parser authors
- If you’re encountering memory limits in compilation, see Memory Limit and Storage Variable Limit settings or try Inform 6 6.36 or higher, which does away with these limits.
Licensing
How to Organize/Structure Your Project
There’s no one answer; here are multiple answers (see games with available source code for examples.)
- Splitting the story into multiple files
- I7 Code Organization and Efficiency
- Juhana Leinonen’s Structuring I7 Code
- Ryan Veeder’s How to Write the Way I Write in I7
- Effective structuring and layout of code
Accessibility
- Using the I7 Windows IDE with NVDA (a screenreader)
Bugs
9.3 is no longer maintained, but 10.1 fixes several bugs in 9.3. You can search for known bugs and their status or report bugs on the I7 bug tracker. If you’re not sure whether you’ve found a bug, post code that shows the issue to the I7 category and ask.
The 6M62 Patches by Friends of I7 extension provides fixes for some known issues in 9.3/6M62.
The Inform 6 that shipped with 9.3/6M62 was 6.33N. The current version is 6.41. Bugs in (the current) Inform 6 can be reported at the Inform 7 bug tracker
The old Inform 7 suggestion forum is accessible via Wayback Machine.
Infrastructure
Inform 6 compiles to your choice of glulx or the Z-machine (v8 only – I7 games don’t fit in the other versions).
Glulx
Most Glulx interpreter apps include one (or more) of:
- glulxe (C), reference implementation
- git (C) (predates the source control system by the same name)
- quixe (Javascript)
Less used are: Zag (Java); Emacs-glulx (Elisp)
Glulx Inform Technical Reference
Glk
Glulx I/O is via the Glk API; glulx terps must be built with a Glk library (Emacs-glulx’ and Zag’s are built-in).
- cheapglk (no window, no status line, just streams of input and output; of interest largely for testing and development)
- glkterm (curses library, widely available for anything UNIX-ish)
- glktermw (“wide char” glkterm for Unicode characters beyond Latin1)
- glkote (Javascript implementation used by Quixe and Lectrote)
- remglk (Receives/emits JSON objects on stdin/stdout; can represent multiple windows and most Glk events)
- CocoaGlk (used by the I7 Mac IDE)
Glk per its spec doesn’t offer the text color control that would be necessary to match the Z-machine. The non-standard Gargoyle Glk extensions can do so. Implementations including them:
- garglk (the Gargoyle multi-system interpreter)
- WindowsGlk (I7 Windows IDE)
- Async Glk @Dannii’s Typescript implementation, used by Parchment / https://iplayif.com
- Chimara GTK3 widget, used by the Linux IDE
- the Glk implementation in Spatterlight
The results of display the boxed quotation
look bad with Glk, thus always with Glulx. Spatterlight, Gargoyle, Lectrote, and Parchment work with both Z-machine and Glulx, but use Glk, so Z-machine games on those inherit boxed text quotes looking bad.
Glk via network:
- remote-if Websockets or AJAX to RemGlk
- glknode HTTP API to cheapglk
- glulxe-httpd HTTP API to cheapglk; support for sessions & transcripts, see langworth.com
References
- Roger Firth and Adam Thornton’s Brief Glk, via Grokking Glk
- The Game Author’s Guide to Glulx Inform and Glulx Inform Technical Reference
- Adam Cadre’s Gull: an introduction to Glulx Inform
Z-machine
Interpreters include:
- the venerable Frotz
- Bocfel, atypically Glk-based; used by Gargoyle; offers interesting comand-line flags: Bocfel’s man page
- ifvms.js, Javascript Z-code interpreter used by Parchment
- gluzma in Glulx assembly
- zig in I6, thus also playable on glulx
- fun ones: Z-machine in hardware, Z-machine on a pen, Folly: Z-machine with handwritten input
References
- Z-machine 1.1 standard, annotated
- Z-machine spec errata
- Z-machine standard: unclear aspects/ambiguities
- Michael Ko’s Internal Secrets of Infocom Games
- Jeff Nyman’s Zifmia: Z-machine terp tests
Tools and Projects
@Zarf’s
- blorbtool.py – manipulate blorbs
- ifsitegen.py – go from a zcode file, glulx file (.ulx), or blorb to a playable website; processes images from blorbs better than I7 itself
- I7 source highlighter with I7 to HTML and Inform 7 to rtf options
- regtest – regression testing for IF running on any interpreter that uses simple input and output streams for I/O, like Frotz’ dfrotz variant or anything built with CheapGlk, or with anything using RemGlk; Nils Fagerburg wrote a regtest bash completion script
- profile-analyze.py – parse profiling data from glulxe (when compiled with the VM_PROFILING flag)
- Atom syntax highlighting
Others
- Jacques Frechet’s glulx-strings extracts all strings from zcode or glulx (even in blorbs); glulx-strings web app
- @Natrium729’s I7 Text Extractor – extracts strings from Inform 7 source (for ease of proofreading)
- Blaze Alan Marshall’s mrifk Glulx reverse compiler and disassembler
- ztools: the Infocom toolkit includes the zcode disassembler txd
- Allen Garvin’s ztool, python port of (most of) ztools
- @Dannii’s glulx to C decompiler (glulxtoc)
- @Juhana’s IF recorder is a Parchment plugin to save transcripts
- Gren Drake’s glulx-assemble (a glulx assembler)
- zzo38’s glasm (a glulx assembler)
- Chris Spiegel’s zdevtools (zcode assembler/disassembler)
- Compile C to Glulx
- reform: reverse compile Z-code to I6
- cBlorb (used by 9.3/6M62; succeeded in 10.1 by inblorb)
Legacy
- Ron Newcomb’s I7 port of the I7 parser (6G60) There have been changes to the parser since this was current, but the documentation section at the bottom constitutes the best documentation of the I7 parser extant.
- Ron Newcomb’s Naga (zip archive) which strips away nearly all of the Standard Library (6G60)
- Textfyre used a modified version of Glulx with different I/O abstractions from GLK
- Erik Temple’s Glimmr graphics framework; Glimmr Github repo; Glimmr archive including demos (6G60)
- Guncho, the multiplayer I7 April Fool’s Day joke that wasn’t
- Brady Garvin’s i7grip Glulx debugger (6G60)
I7 in translation
- Manifesto for the translation of I7 (PDF) (6G60) by Graham Nelson
- Swedish (6G60) by Felix Larsson
- Italian (6M62) by Massimo Stella, maintained by Leonardo Boselli
- French (6L38) by Nathanaël Marion
- Spanish (6M62) by Sebastian Arg (see also centro de documentación Inform 7)
- German (6G60) by Team GerX
Hosting
- You can upload your game to the IF Archive; once accepted, pass its URL to IPlayIF.com, the resulting URL will be to a playable-online copy of your game. (See, e.g., many games on IFDB)
- Borogove.io hosts games online for free, either uploaded or built with borogove.app
- Playfic is similar but uses 6G60
- if you release along with an interpreter the resuling file directory would make your game playable if you uploaded it anywhere on the web, provided that the website would deliver them as regular web pages and not just downloads. Google drive, for instance, wouldn’t work for this. A (free) itch.io account would work; games on itch.io can be private or shared just with playtesters
Miscellany
IFwiki’s rec.arts.int-fiction threads on Inform 7
Ryan Veeder’s Basic Autosaving, Advanced Autosaving, Additional Autosaving Techniques
Jeff Nyman:
- The Hitchhiker’s Guide to Inform 7: All About Rules (c. 5U92)
- The Hitchhiker’s Guide to Inform 7: Relations (c. 5U92)
- The Well-Versed Informer (PDF) (5Z71)
- The Well-Versed Informer: Foundations (PDF) (5Z71)
- The Well-Versed Informer: Descriptions and Locale (PDF) (5Z71)
- Introduction to I7 (c. 6L02)
- The Rules of I7 (c. 6L02)
- The Actions of I7 (c. 6L02)
@mathbrush’s 77 Verbs serves as a trainer in default available commands.
Updating Code written for 6G60
John Timmons’ Inform Snippets and Inform Manual (PDF) (c. 5U92-6F95)
inform7tips: fresh I7 tidbits Monday-Friday.
Archived I7 website sitemap: many links above are to archive.org copies of pages no longer on the Inform 7 website.
Language Comparisons
IF Resource Links has much more of interest to IF authors in general, not specific to I7.
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